1. Field of the Invention
This invention relates to the three dimensional imaging of objects using radiated pulses of energy.
2. Description of the Prior Art
Heretofore imaging of three dimensional volumes was accomplished using multiple sequentially transmitted pulses. Each transmission and its associated echoes yields information on only a small portion of the volume. Thus it would take a relatively long time to image a three dimensional volume of significant spatial extent.
U.S. Pat. No. 4,332,016 describes an ultrasonic device for three dimensional imaging of objects using a narrow beam of insonification formed by a transmitted pulse. The objects to be imaged are mechanically moved past the beam and insonified repeatedly with transmitted pulses thus taking a relatively long time to form a complete image and in addition requiring a plurality of transmitting transducers.
U.S. Pat. No. 3,918,025 describes an ultrasonic device for three dimensional imaging using a frequency swept pulse of ultrasonic energy. However because of a frequency swept transmission the echoes from the object field will exhibit many interference effects that will vary as a function of their angular position. By means of the frequency sweep this device essentially electronically scans a continuous fan shaped beam over a field of objects and thus does not insonify the object field simultaneously with a single transmitted pulse and thus requires a longer time to obtain a three dimensional image.
U.S. Pat. Re. No. 30,397 describes an ultrasonic device for three dimensional imaging using a two dimensional real time scanner physically scanned in directions orthogonal to its tomographic plane and thus require a relatively long time to obtain a three dimensional image.
U.S. Pat. No. 4,131,022 describes an ultrasonic device for three dimensional imaging. However this device uses a scanned beam of ultrasonic energy and requires a longer time to completely image a volume.